In the General Help section there are a bunch of threads about this topic: Pinto Steering, Steering shaft, Steering Rag Joint Pics?, Rag joint help, A little help is needed, Steering joint help please!!, Steering wheel slack? (and maybe a few others too).
Due to the number of people requesting information on Pinto steering "rag joints", I thought I would post some info here. Please note these are not "instructions", just general information on this topic.
Ford used a disc made of plastic in the joint, and it seems that a good number of them fail (if not all). There is a safety bracket assy. on the joint to keep steering control WHEN the disc fails, it makes the steering very sloppy and noisy, but you will have steering control at least for a while. When in use (failed disc), the safety bracket has metal to metal contact on the shaft, it WILL wear and possibly fail at some point too, leaving the car with NO steering; this is why it is CRITICAL to replace the disc.
The disc can fail just from age, improper maintenance, heat, poor road conditions, or from a crash. If the joint has been changed with a rubber disc it can fail too from being oil soaked, improper installation, or the reasons mentioned for the stock disc.
I have found the best way to change the joint is to remove the shaft/joint from the car. Also, I have found that the pins that hold the plastic disc are not threaded, but are rivets and need to be drilled out. This is not to say that all of them are like that, but on the ones I have worked on anyway.
After looking at a bunch of parts stores, I have not found a direct replacement part # for a Pinto, but NAPA has a kit that is NOT for a Pinto, and the disc fits. Napa # 630-1012. It has been a while, but from what I remember you might need to buy a bolt or two and some washers to install the disc from this kit. Use LOCK NUTS (non-plastic), insure that the lock feature is engaged, ALWAYS re-install the safety bracket, and do not over tighten the bolts and crush the rubber.
I have never checked to see if Ford still has them available, but I would assume IF they did it would be an assy. with the shaft (and VERY expensive).
One time I made a disc from the side wall of an old tire (IMHO, if you can remove the shaft and install a new disc, you CAN make a disc too). The new ones look like tire side walls anyway, and I just installed it with bolts and LOCK NUTS. Again, I was careful not to crush the rubber disc, and I reccamend some sort of spacer on the bolts too if you have them (or the correct shank length on the bolts).
From time to time I see NOS rag joints and shafts on ebay from $30. to $100., but with the age that they are, they might be short lived.
Steering is very critical for driving safety, if you are not 100% comfortable with doing work to this system, have your car repaired by a licensed automotive repair facility.
Bill
ADDED 6 Feb 07: I picked up a rag joint repair from NAPA, part # 630-1008, and it worked fine. This one is listed for Pintos from 71 to 75 in the NAPA book.